A broad array of hand-held navigation and input devices are known in the art, such as mice, pens and styluses. Such input devices operate in a number of fashions. For example, optical computer mice provide (X, Y) positions of the mice as they navigate atop and across navigation surfaces. Other input devices such as styluses and pens are often used in conjunction with capacitive touch screens, touch pads and other types of active backplanes or navigation surfaces to indicate the (X,Y) position of a stylus or pen as is moved across the navigation surface.
One notable shortcoming of many such input devices and systems is that they may be incapable of operating properly when lifted vertically from the navigation surface as they are moved laterally across the navigation surface. For example, when the vertical distance by which such an input device is lifted off the navigation surface exceeds tightly constrained design maxima exceeding say a millimeter or two, the ability to navigate and provide accurate (X,Y) positions to the computer or other device to which the device is operably linked is lost. Moreover, and in the case of some pens or styluses, rather complicated and expensive navigation substrates or surfaces such as specialized electronic writing surfaces, active backplanes, capacitive touch screens, and the electronic circuitry associated therewith, is required to provide and report the (X,Y) positions of the pen or stylus as it is moved across the navigation surface or substrate.
In the case of a pen-shaped optical mouse employed to record handwriting input by a user, changes in vertical spacing between the pen-shaped optical mouse and the navigation surface can wreak havoc in the ability to accurately record the (X,Y) movements and positions of the pen-shaped optical mouse as it is moved across and atop the navigation surface. These shortcomings are typically exacerbated when writing is done using Kanji, Hanzi, Arabic or other sets of writing characters owing to the complicated natures of the characters themselves, as well as errors introduced by vertical movements of the pen-shaped optical mouse. For example, problems in faithfully recording (X,Y) positions of a pen-shaped optical mouse may be introduced by way of the natural and frequent tendency of many users to lift the pen-shaped optical mouse from the writing medium as they write.
What is needed is a navigation input device capable of reliably and accurately reporting (X,Y) positions as the device is moved across a navigation surface notwithstanding vertical movements of the device that occur as the device is being moved. What is also needed is an input system that does not require the use of complicated and expensive navigation substrates such as active backplanes, touch screens, or touch pads.